1
INDEX
Committees………. 2
Plenary talks……… 3
Abstracts (by alphabetical order)
Oral presentations……….……….. 8
Poster presentations……….. 151
List of supporters………. 436
2
COMMITTEES
Conference host
Pyrenean Institute of Ecology, Spanish National Research Council (IPE-CSIC)
Av/ Montañana 1005
50059 Zaragoza
Spain
Phone: +34 976369393
Fax: +34 974363222
www.ipe.csic.es
Local Organizing Committee
Blas Valero-Garcés, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Ana Moreno, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Penélope González-Sampériz, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Graciela Gil-Romera, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
José Mª García-Ruiz, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Juan Ignacio López-Moreno, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Jesús Julio Camarero, Pyrenean Institute of Ecology, CSIC, Zaragoza, Spain
Pilar Utrilla, University of Zaragoza (Prehistory), Zaragoza, Spain
Lourdes Montes, University of Zaragoza (Prehistory), Zaragoza, Spain
Rafael Domingo, University of Zaragoza (Prehistory), Zaragoza, Spain
Carlos Sancho, University of Zaragoza (Geology), Zaragoza, Spain
Gloria Cuenca, University of Zaragoza (Geology), Zaragoza, Spain
OSM Scientific Program Committee
Hubertus Fischer, University of Bern, Switzerland
Sheri Fritz, University of Nebraska, USA
Marie-France Loutre, PAGES IPO, Switzerland
Lucien von Gunten, PAGES IPO, Switzerland
Janet Wilmshurst, Landcare Research, New Zealand
Liping Zhou, Peking University, China
Pascale Braconnot, LSCE, France
Hugues Goosse, Université catholique de Louvain, Belgium
Yusuke Yokoyama, University of Tokyo, Japan
Blas Valero-Garcés, IPE-CSIC, Spain
Ana Moreno, IPE-CSIC, Spain
3
PLENARY TALKS
Wednesday 9:30-10:00
Early onset of industrial-era warming across the
oceans and continents
Nerilie Abram
11) Research School of Earth Sciences, The
Australian National University, ACT 2601 Australia
and ARC Centre of Excellence for Climate System
Science, The Australian National University, ACT
2601 Australia
* Nerilie Abram,
nerilie.abram@anu.edu.au
The evolution of industrial-era warming provides
critical context for future climate change, and has
fundamental importance for determining climate
sensitivity and the processes that control regional
warming over land and in the oceans. We use
post-1500CE palaeoclimate records to show that
sustained industrial-era warming of the tropical
oceans first developed during the mid-19th
Century, and was near-synchronous with Northern
Hemisphere continental warming. The early onset
of sustained, significant warming in palaeoclimate
records
and
model
simulations
suggests
greenhouse forcing of industrial-era warming
commenced as early as the mid-19th Century, and
included an enhanced equatorial ocean response
mechanism. The development of Southern
Hemisphere warming is delayed in continent-scale
reconstructions, developing around the end of the
19th Century over mid-latitude continents and not
yet evident at the continent scale over Antarctica.
This apparent delay is not reproduced in climate
simulations, but further regional analysis of an
expanded array of Antarctic palaeoclimate records
supports the delayed development of warming
here and may be related to Southern Ocean
circulation processes. Our findings imply that
instrumental
records
are
too
short
to
comprehensively assess anthropogenic climate
change, and in some regions ~180 years of
industrial-era warming has already caused surface
temperatures to emerge above pre-industrial
variability.
Wednesday 10:00-10:30
The future of old things: geoinformatics for
better paleoscience
Julien Emile-Geay
1, Nicholas P. McKay
2, Yolanda
Gil
3, Deborah Khider
1, Daniel Garijo
3, Varun
Ratnakar
31) Dpt of Earth Sciences, University of Southern
California, Los Angeles, CA, USA
2) School of Earth Sciences and Environmental
Sustainability, Northern Arizona University,
3) Information Sciences Institute, University of
Southern California, Los Angeles, CA, USA
* Julien Emile-geay,
julieneg@usc.edu
By some accounts, paleoscientists spend up to
80% of their time trying to access the data they
need, in the form they need it. In the 21st century,
we should be able to do much better.This lecture
will review recent progress made by the
LinkedEarth project, which relies on data
standards and artificial intelligence to enable
scientists to spend more time doing the science
they want to do.LinkedEarth is manifesting a
better future for paleoscience by creating an
online platform that (1) enables the curation of a
publicly-accessible database by paleoclimate
experts themselves, and (2) fosters the
development of community standards. In turn,
these developments enable cutting-edge
data-analytic tools to be built and applied to a wider
array of datasets than ever possible before,
supporting more rigorous assessments of the
magnitude and rates of pre-industrial climate
change.We will start by illustrating these
principles in the context of the PAGES2k project,
and outline how they may serve the PAGES
community as a whole. In particular, we will
illustrate how to go from spreadsheets to
syntheses (PAGES2k). We will dwell on community
participation in the first paleoclimate data
standard. We will present GeoChronR and
Pyleoclim, new open-source tools compatible with
these standards and enabling cutting-edge
paleoscience. We will finish by some remarks on
interoperability, enabling cross-talk between
scientists within a field, across fields, and between
data and models.In our vision of the future,
4
machines serve scientists, not the other way
around. Yet, the process needs a lot of human
input, and the participation of the PAGES
community will be recognized and further
encouraged.
Thursday 9:00-9:30
Determining the causes of climate change: from
large scale temperatures to extreme events
Gabriele Hegerl
1, Andrew Schurer
1, Tim Cowan
1,
Carley Iles
1, Juerg Luterbacher
1, Simon Tett
11) University of Edinburgh
* Gabi Hegerl ,
gabi.hegerl@ed.ac.uk
Attribution of climate change to causes and
Attribution of changing risk of extreme events
both require reliable information about climate
variability and change. The grand challenge team
on extreme events highlights the need to better
observe, understand, attribute and simulate
extreme events. A short introduction to the
approach of the grand challenge is given, followed
by a discussion of its relevance to palaeoclimate.
Two examples are discussed: Many drought
reconstructions are available and there is
evidence for very significant drought events in the
past. As an example, the historical dust bowl
drought and associated heat waves are compared
to events that occur in climate model simulations.
As a mechanism, sprint moisture preconditioning
appears important, while links to decadal
variability connected to sea surface temperature
appear unclear and model dependent for that
region. When considering a possible role of
external forcing in drought, it is important to
consider the expected pattern of the response,
which can be complex over land. Nevertheless,
long streamflow data support broadly a wettening
of dry regions, and drying of wet regions following
volcanic eruptions. The second example focuses
on extremely cold conditions also following
volcanic eruptions. While overall, reconstructions
tend to show a weaker response to volcanic
eruptions than simulated, some of the most
extreme cold conditions of Europe occurred in the
1810s. Simulations suggest that this period around
the
eruption
of
Mount
Tambora
was
systematically colder than the preindustrial
climate in general. Attribution analyses shows that
the volcanic eruptions are a key driver of these
cool conditions, with only a weak contribution
estimated from solar forcing. However, other
aspects of the cold conditions, for example, in
Central Europe, appear atypical for volcanic
eruptions. Attribution methods can address to
what extent events such as these are random
weather variability, or what fraction of the risk of
cold conditions can be linked to the volcanic
eruption.
Thursday 10:00-10:30
Exploring atmosphere-ocean connections in the
Western Mediterranean region during past
climatic transitions: last terminations, glacial
inceptions and some Holocene key changes
Isabel Cacho
1, Ana Moreno
2, Heather Stoll
3,
OPERA team
41) GRC Geociències marines, Dept. Dinàmica de la
Terra i l'Oceà, Universitat de Barcelona
2) Pyrenean Institute of Ecology, CSIC, Zaragoza,
Spain
3) Dept. Erdwissenschaften, ETH Zurich, Zürich,
Switzerland
4) Universitat de Barcelona, Universidad de
Zaragoza, Universidad de Oviedo, Universitat de
les Illes Balears, IPE CSIC, University of Minnesota,
Xian Jiaotong University
* Isabel Cacho,
icacho@ub.edu
The Mediterranean region is an exceptional
sensor of climatic variability and in particular, the
western Mediterranean Sea has demonstrated a
tight connection with changes in the Atlantic
Meridional Overturning Circulation (AMOC). Such
a connection is further explored through an
integrated study of cave speleothems and marine
sediments reflecting climate conditions along the
Iberian Peninsula. New speleothem records
covering a transect from the most Atlantic to the
most Mediterranean sectors across the Iberian
Peninsula provide solid chronologies from Marine
Isotopic Stage (MIS) 7 to 4 covering Terminations
III and II and subsequent glacial inceptions. A clear
picture stands out with a strong coupling between
intense aridity phases and cold stadial conditions
linked to AMOC weakening events and also to
changes in the Mediterranean thermohaline
circulation. In contrast, a high resolution Younger
Dryas speleothem record breaks with this overall
5
stadial pattern showing an intra-event transition
from extreme arid toward wetter conditions
which is linked to circulation changes in the
Atlantic Ocean. Temperature and humidity
changes along the Holocene show a more complex
pattern. A new high resolution W-Mediterranean
surface temperature record supports maximum
temperatures during the early Holocene while
records from the north to the south of Iberia
indicate limited water availability. Maximum in
water availability occurred between 9-7 ka BP
followed by an overall reduction in humidity,
whose timing and pattern changes very much
among the records, likely reflecting different
proxy
sensitivity,
seasonality
or
regional
diachrony. Finally, both speleothem and marine
records show significant variability in temperature
and humidity pattern along the last 2 kyr,
particularly the Little Ice Age appears as a very
unstable climatic period where two different
phases can be differentiated in terms of
temperature and rain patterns, the main driver of
the short term variability of this period seems to
be associated to the Atlantic Multi-decadal
Oscillation.
Thursday 10:00-10:30
Human evolution and climate
Juan Luis Arsuaga
11) Universidad Complutense de Madrid
* Juan Luis Arsuaga,
jlarfer@gmail.com
We look around and see all the animals well
adapted to their respective ecological niches. They
have had enough time to adapt. Natural selection,
Darwin´s favorite mechanism for evolution, has
done a good job with them. The unfitted were
eliminated in the struggle for life, long time ago.
Today natural selection should be only a
normalizing force. Then, why do species evolve?
Darwin was well aware of this problem and
thought he had found the solution: the
environment changes. The fittest today could be
misfits tomorrow.In a similar way, climatic and,
consequently, ecological changes haven been
considered a driving force in human evolution. For
the origin of the hominins in the different African
East Side stories, to begin with. And for the rise
and demise of the Neanderthals in the dark and
freezing
European
Ice
Ages.
Neanderthal
specializations have been interpreted as artic
adaptations by some scholars, and yet there are
colleagues who state that Neanderthals could not
survive the Last Glaciation environmental
challenge. They were not outcompeted by
modern humans, it is said, Neandertals went
extinct for just the same reason that other warm
adapted European mammals. Their world
vanished.In this lecture the current evidence for
the role of the climate in the European
Pleistocene hominin evolution is critically revised.
Friday 9:00-9:30
Warm worlds – features and lessons from the
Quaternary interglacials
Eric Wolff and the PAGES Past Interglacials
Working Group
11) Department of Earth Sciences, University of
Cambridge, Downing Street, Cambridge, CB2 3EQ,
UK
* Eric Wolff,
ew428@cam.ac.uk
Worlds that are warmer than today have a
particular relevance for the future. The Pliocene
had higher CO2 concentrations, comparable to
those of today, but data to infer the climatic
effects are rather sparse. The Holocene has a
wealth of data but rather muted climate changes
in many places. Some Quaternary interglacials
offer a reasonable amount of data on both
forcings and response, and significant differences
in climate. However, interpretation is complex
because the forcings and responses have a
regional character that makes them only partially
analogous
to
anything
expected
in
the
future.Interglacials are warm, low land-ice extent
(high sea–level), end members of glacial cycles.
Concentrating mainly on last 800,000 years, we
first explore different definitions of interglacials to
understand what the population of the species
“interglacial” is. We use a quasi-sea level
definition to identify 11 interglacials in the last
800 ka. Considering both astronomical forcing and
glacial maximum ice volume, we can tentatively
identify why this may be the case.Having
identified the group members, we study their
diversity. Marine, ice and terrestrial data
compilations suggest that, despite spatial
heterogeneity, Marine Isotope Stages (MIS) 5e
(last interglacial) and 11c (~400 ka ago) were
6
globally strong (warm), while MIS 13a (~500 ka
ago) was cool at many locations. The onset of an
interglacial (glacial termination) seems to require
a reducing precession parameter (increasing
northern hemisphere summer insolation), but this
condition alone is insufficient. Terminations
involve rapid, non-linear, reactions of ice volume,
CO2 and temperature to external astronomical
forcing. The precise timing of events may be
modulated by millennial-scale climate change that
can lead to a contrasting timing of maximum
interglacial intensity in each hemisphere. This will
be illustrated particularly for the case of MIS5e,
and I will emphasise the implications of this
interglacial for ice sheet stability.
Friday 9:30-10:00
Future Earth – vision, mission and opportunities
Hannah Moersberger
11) Future Earth, Global Hub in Paris, France
*
hannah.moersberger@futureearth.org
Future Earth is a global platform for sustainability
research, aiming at advancing global sustainability
science, building relevant research capacities and
providing
an
international
interdisciplinary
research agenda. The 10-year programme
produces the knowledge and support to
accelerate transformations to a sustainable world.
Future Earth is built on more than three decades
of international research on global environmental
change carried out by projects sponsored by
DIVERSITAS, IGBP and IHDP. PAGES has become
one of Future Earth’s global research projects in
2015.The presentation will give an overview of
Future Earth’s vision and mission, as well as its
current
activities.
Our
Knowledge-Action
Networks as the main mechanism to connect
science with society invite researchers from all
kinds of disciplines and backgrounds to get
engaged. Their scope covers a broad range of
topics, from oceans and natural assets to
transformations, the SDGs and financial and
economic systems.
Saturday 17:15-17:45
New observations of past, fast changes in
greenhouse gases
Edward Brook
1, Rachael Rhodes
2, Shaun
Marcott
3, James Lee
1, Jon Edwards
1, Thomas
Bauska
2, Jinho Ahn
4, Michael Kalk
1, Jochen
Schmitt
5, Hubertus Fischer
51) College of Earth, Ocean, and Atmospheric
Sciences, Oregon State University, Corvallis, OR,
USA
2) Department of Earth Sciences, University of
Cambridge, Cambridge, UK
3) Department of Geoscience, University of
Wisconsin, Madison, WI, USA
4) School of Earth and Environmental Sciences,
Seoul National University, Seoul, Korea
5) Climate and Environmental Physics, Physics
Institute & Oeschger Centre for Climate Change
Research, University of Bern, Bern, Switzerland
* Edward Brook,
brooke@geo.oregonstate.edu
Advances in measurement technology and new
archives now allow the resolution of ice core gas
records to approach or exceed the atmospheric
lifetimes of methane, carbon dioxide, and nitrous
oxide. Detail at this level provides insight in to
mechanisms that control natural variability and
feedbacks in the climate system on time scales
relevant to human impacts on the earth system.
This presentation provides an overview of new
carbon dioxide and methane results, primarily
from the WAIS Divide ice core in Antarctica, that
reveal new aspects of the relationship between
abrupt climate change and greenhouse gas
biogeochemistry.
Continuous
records
of
atmospheric methane from WAIS Divide fully
document the well-known variations tied to the
Greenlandic stadial-interstadial variability, linked
by multiple lines of evidence to changes in low
latitude methane emissions. This and other
records also reveal a) abrupt shifts in the baseline
methane concentration during some Heinrich
stadials, probably tied to the impact of Heinrich
events on tropical hydrology, and b) persistent but
enigmatic centennial variability in the Holocene
and last glacial period. Carbon dioxide variations
during the last ice age and deglaciation generally
correlate with Antarctic temperature, but in detail
seem comprised of variability on different time
7
scales. Coincident, abrupt increases in methane
and carbon dioxide during some Heinrich stadials
delineate a new type of abrupt event, probably
related to southward migration of tropical rainfall
belts causing increased methane emissions. The
synchronous carbon dioxide variations could also
have a terrestrial source, for example due to
drying in the northern tropics, but there are viable
mechanisms linked to changes in ocean circulation
or biogeochemistry.
Saturday 17:45-18:15
Climate variability, vegetation dynamics and
human-environment
in
continental
Mediterranean Iberia during last glacial cycle
Penélope González‐Sampériz
11) Pyrenean Institute of Ecology-CSIC, Av/
Montañana s/n, 50059 Zaragoza (Spain)
*
pgonzal@ipe.csic.es
The inland areas of Mediterranean Iberia are
vulnerable regions to Global Change impacts as
they are characterized by extreme climate
conditions in terms of both temperature and
precipitation. Humans have faced abrupt
environmental and climate changes in these
territories through the last glacial cycle and those
synergies illustrate the PAGES initiative: the
climate-humans-environment
interactions
through time.New records have changed our
understanding
of
the
palaeoenvironmental
framework for inner Iberia during the last glacial
cycle. The current complex biogeographical
context of the Iberian Peninsula is a reflection of a
complex palaeoenvironmental history, with
unexpected trends and impacts in both vegetation
landscape and hydrological processes, compared
with coastal areas, Atlantic and more typical
Mediterranean regions. Patterns of cultural and
socioeconomic evolution also show distinctive
characteristics.Not
surprisingly,
terrestrial
vegetation in continental Iberia shows a resilient
behaviour during millennial – scale evolution and
short periods of abrupt climate change, despite,
interestingly, nearby locations respond as
expected to abrupt changes with similar evolution
in terms of taxa composition to Mediterranean
and/or Eurosiberian sites. Besides, vegetation
dynamics usually followed local, or even regional,
palaeohydrological conditions but not always
global
millennial-scale
climate
variability.
Asynchrony in both timing of the local last glacial
maximum and humidity onset at the beginning of
the Holocene are two clear examples of this
complex scenario. Additionally, hunter-gathered
groups likely responded to abrupt events with
migration episodes, but there are too a number of
examples of diverse responses to hydrological
crises during deglaciation and the Holocene.
Timing and intensity of first anthropogenic impact
is also very variable along the whole territory.All
these "apparent inconsistencies" are probably the
result of an incomplete record but also illustrate
the
great
heterogeneity
inherent
to
Mediterranean regions. Interpretations of past
human interactions with the landscape become
more difficult in regions with extreme events,
resilient vegetation and variable landscape
dynamics. But they also provide an opportunity to
improve our knowledge about Earth’s past
environment at local-regional scales, in order to
obtain better and more detailed scenarios of
human interactions with future climate and
environment changes, as PAGES promotes and
society demands.
8
ORAL PRESENTATIONS
(by alphabetical order of first author surname)
9
ID: 02156, 08.- Volcanic eruptions: the thread connecting climate records, societal change and future climate projections?, (Oral)¬Tracing Marine Cryptotephras in the North Atlantic during the Last Glacial Period
Peter Abbott1 , Siwan Davies2 , Adam Griggs2 , Anna Bourne3 1) Institute of Geological Sciences, University of Bern, Switzerland and School of Earth and Ocean Sciences, Cardiff University, UK 2) Department of Geography, Swansea University, UK 3) Geography and Environment, University of Southampton, UK * Peter Abbott, abbottp@cardiff.ac.uk
There is high potential to utilise tephrochronology to integrate palaeoclimatic records from the North Atlantic region to study climatic phasing, due to the high eruptive frequency of Icelandic volcanoes. However, until now North Atlantic marine records have been relatively understudied. Here we report on investigations to define a tephra framework integrating new studies of cryptotephra horizons within a wide network of marine cores with horizons identified in prior work. This framework has the potential to underpin the correlation of the marine records to the Greenland ice-core records and European terrestrial sequences.
Investigations were conducted on 13 marine sequences using cryptotephra extraction techniques to gain glass shard concentration profiles and single-shard major element geochemical analysis to characterise identified deposits. Cryptotephras were identified in many records, displaying diversity in shard concentration profiles and geochemical homo/heterogeneity. These differences reflect spatial and temporal variability in the operation of a range of transport processes, e.g. airfall, sea-ice and iceberg rafting, and post-depositional processes, e.g. bioturbation and secondary redeposition. These processes can impart a temporal delay on tephra deposition and hamper the placement of the isochron, therefore, their influence is assessed. A range of deposit types with common transport and depositional histories have been defined. Spatial patterns in the occurrence of these deposit types have been detected, the dominant controls at different sites explored and key regions preserving isochronous deposits identified.
Overall, a framework of isochronous marine cryptotephras has been defined for the last glacial period. The most widespread deposit is the rhyolitic phase of NAAZ II, identified in 9 of the marine sequences and providing a direct tie-line to the Greenland ice-cores records. The framework is dominated by horizons with a basaltic composition, predominantly sourced from the Icelandic Grímsvötn volcanic system but horizons with Katla, Hekla, Kverkfjöll, Veidivötn and Vestmannaeyjar-like compositions have also been isolated.
ID: 01945, 14.- Hydroclimate variability through the ages: Data, models, mechanisms, (Oral)
Indian Ocean Dipole variability during the last millennium
Nerilie Abram1 , Bethany Ellis1 , Bronwyn Dixon2 , Wahyoe Hantoro3 , Chuan-Chou Shen4 1) Research School of Earth Sciences and ARC Centre of Excellence for Climate System Science, Australian National University, ACT 2601, Australia 2) School of Geography, University of Melbourne, Victoria 3010, Australia 3) Research Centre of Geotechnology, Indonesian Institute of Sciences, Bandung 40135, Indonesia 4) High-precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan ROC * Nerilie Abram, nerilie.abram@anu.edu.au
The Indian Ocean Dipole (IOD) is a mode of coupled ocean-atmosphere variability that severely impacts rainfall patterns in nations surrounding the Indian Ocean. Coral-based reconstructions of IOD variability since the mid 19th Century suggest that there has been a significant increase in the frequency and magnitude of positive IOD events in recent decades. Climate model simulations also indicate that the rainfall impacts of extreme IOD events will intensify in a warming world, however confidence is limited by known biases in model representations of the IOD. Here we use an array of fossil coral records from the eastern equatorial Indian Ocean – where the signature of IOD variability is optimised – to produce a semi-continuous reconstruction of IOD variability during the last millennium. This reconstruction includes coverage during the Medieval Warm Period, Little Ice Age and pre-industrial periods, as well as following major volcanic eruptions of the last millennium. We use these records alongside ensembles of climate simulations to assess the factors that have caused changes in the frequency and characteristics of IOD variability in the past, and to provide valuable perspectives on the apparent and predicted intensification of IOD activity during the 20th and 21st Centuries.
ID: 01241, 24.- Regional versus global in past monsoon dynamic: disentangling wind and precipitation proxies., (Oral)
Late Quaternary record of changes in the planktonic foraminiferal abundance in the north to south transect of the Andaman Sea: inferences on monsoon climate Sijinkumar Adukkamveedu1 , B N Nath2 , Steven Clemens3 , S M Ahmad4 , S M Gupta2 , A Aldahan5 , G Possnert6 , N Lathika7 1) Department of Geology, School of Earth Science Systems, Central University of Kerala, Kerala , India 2) CSIR-National Institute of Oceanography, Dona Paula, Goa, India 3) Earth, Environmental, and
10
Planetary Sciences, Brown University, Providence, RI, USA 4) CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad, India 5) Department of Earth Sciences, Uppsala University, Uppsala, Sweden 6) Tandem Laboratory, Uppsala University, Uppsala, Sweden 7) National Centre for Antarctic and Ocean Research, Vasco Da Gama, Goa, India * Sijin Kumar Adukkam Veedu, sijingeo@gmail.comLate Quaternary climate and oceanographic conditions of the Andaman Sea is rarely studied and the available paleo records are limited to oxygen isotopic and magnetic properties. We present here the downcore variations in planktonic foraminifera assemblages along with oxygen isotope and geochemical proxies of three well-dated cores collected from the north–south transect of the Andaman Sea. Age controls of the cores are based on accelerator mass spectrometry (AMS) dates on mixed planktonic foraminifera. The proxy profiles show glacial-Holocene millennial scale monsoonal climate changes and associated productivity fluctuations. Large variations in river runoff, productivity and water column stratification is seen associated with summer monsoon evolution from last glacial to Holocene. Intensification of the summer monsoon started in the early stages of the Bølling/Allerød (B/A; 15-13.5 ka) followed by slight weakening during the Younger Dryas (YD) and regained strength during early Holocene, coinciding with the highest summer insolation at 30˚N. This enhanced summer monsoon during early to mid-Holocene resulted in huge fresh water runoff that slowly muted upwelling and productivity by intense stratification. Summer monsoon was weaker during Heinrich Event 1 (H1), late Glacial (19-16 ka), Last Glacial Maximum (LGM), 38 – 34 cal ka BP and 46-41 cal ka BP. A progressive gradual decline in the total planktic foraminifera abundances from early Holocene to present suggests a gradual weakening of the summer monsoon. Our records show that monsoon variability in the last 55 ka has been controlled by variation in solar insolation, Atlantic teleconnection on Heinrich and Dansgaard-Oeschger time scale and finally shifting feedback associated with summer-winter monsoon interaction.
ID: 01715, 16.- Multidisciplinary reconstruction of paleofloods, (Oral)
Late Pleistocene outburst floods of the ice-dammed lakes and climate changes in the highlands of the SW Tuva, mountains of Southern Siberia
Anna Agatova1 , Roman Nepop1 1) Institute of Geology and Mineralogy 2) Ural Federal University * Anna Agatova, agatr@mail.ru
We present the results of our multidisciplinary investigations of the SW Tuva highlands, which is the watershed of two basins: the Arctic Ocean and the inland drainage basin of Mongolia. During Pleistocene
glaciations, glaciers extended repeatedly from the mountain ranges along the major valleys and impounded extensive lakes within the depressions. Subsequent ice-dam failures led to outburst floods. All these processes were controlled by the Global climate changes and are evidenced by numerous specific landforms and sediments.In the framework of presented study generally 11 sections were studied and 15 new radiocarbon ages of deposits of different genesis were obtained.
New data suggest the existence of significantly larger lakes in the region. We also present evidences of the outbursts floods from these ice-dammed lakes and describe landforms and sediments associated with these flooding events.
Available absolute dates suggest some chronological stages of the late Pleistocene – Holocene regional hydrological system transformation controlled by climate changes. Period of prolonged climate deterioration followed by the development of spacious glaciations and related formation of ice-dammed lakes took place earlier 14000 years ago. Early Holocene climate warming accompanied by degradation of the ice sheet determined further stages of ice-dammed lakes development and draining. We can state that no later than 8000 years ago the water level in some lakes significantly declined and after their final drying approximately to the modern size there were only climatically driven oscillations of their filling.
Favorable climate conditions (more warm and humid in comparison with the modern ones) about 3000-3500 years ago was evidenced by soil formation and wide spread of forest vegetation in treeless modern landscape of the region. In 6th – 2nd centuries BC the area was widely settled by nomads associated with the Saglyn culture of Scythian epoch.
ID: 01404, 19.- Do species move, adapt or die? Exploring past biodiversity, ecological change and community dynamics in the fossil record, (Oral)
The Pleistocene fish fauna along the eastern coast of Rhodes Island (eastern Mediterranean)
Konstantina Agiadi1 , Angela Girone2 , Efterpi Koskeridou1 , Pierre Moissette3 , Jean-Jacques Cornée4 , Frédéric Quillévéré3 , Vasileios Karakitsios1 1) National and Kapodistrian University of Athens 2) Università degli studi di Bari 3) Université Lyon 1 4) Université
Montpellier 2
* Konstantina Agiadi, kagiadi@geol.uoa.grThe teleost assemblages identified in the Pleistocene sediments of the eastern part of Rhodes Island (southeastern Aegean Sea) exhibit a similar structure to the present-day eastern Mediterranean ones. Epipelagic fish include anchovies, sardines, and horse mackerels, whereas lanternfishes dominate the mesopelagic domain. The most numerous
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and diverse benthic and benthopelagic families are congrids, gadids, sparids, and gobiids. A gradual replacement of pelagic tropical-subtropical species by subtropical-temperate ones, in both the neritic and the oceanic domain, took place from the Gelasian until the Ionian stage. The distribution of pelagic taxa during the Pleistocene appears to be mostly related to climate variability at local and global scale. However, the benthic neritic community did not suffer as well, since most of the species remain present in the southeastern Aegean until today. In the deep water, benthic and benthopelagic taxa have been gradually removed from this area, favoring colder-water inhabitants. The otolith assemblages identified in the Pleistocene sediments of Rhodes Island significantly enhance the eastern Mediterranean fish fauna Cenozoic record, which has so far relied only on scarce and fragmentary skeletal remains.ID: 01296, 16.- Multidisciplinary reconstruction of paleofloods, (Oral)
Frequent extreme rainstorms during late Holocene regional drought in the Dead Sea basin
Marieke Ahlborn1 , Moshe Armon2 , Yoav Ben Dor2 , Achim Brauer1 , Efrat Morin2 , Ina Neugebauer3 , Markus J. Schwab1 , Rik Tjallingii1 , Yehouda Enzel2 1) Section 5.2: Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Potsdam, Germany 2) Institute of Earth Sciences, The Hebrew University, Jerusalem, Israel 3) Department of Earth Sciences, University of Geneva, Geneva, Switzerland * Marieke Ahlborn, marieke@gfz-potsdam.de
Linking the frequency of extreme-flow-producing rainstorms and the long-term climate trends is essential for assessing the impacts of global and regional climate change. Our results present rare evidence of increased frequency of torrential rainstorms likely associated with the Active Red Sea Trough during a multi-century regional drought in the eastern Mediterranean.
We studied a shallow water sediment core from the Dead Sea to establish a time series of torrential rainstorms for the time interval between 3.3 and 1.8 cal ka BP. Microfacies analysis allowed the identification of 23 discrete graded layers formed by debris flows originating from the nearby steep western escarpments of the Dead Sea. Modern observations show that debris flows are triggered by exceptionally heavy torrential rainstorms over the escarpments, which exceed an estimated threshold of at least >30 mm h-1 for the duration of one hour. Such rainstorms are synoptically associated with the intrusion of the Active Red Sea Trough into the Dead Sea catchment. An increased frequency of torrential rainstorms during a regional drought (3.0-2.4 cal ka BP), as suggested by our data, indicates a shift in the prevailing synoptic-scale atmospheric circulation pattern.
In particular, we suggest that the drought was caused by a decreased frequency of eastern Mediterranean cyclones and thereby allowed the increased frequency of the Active Red Sea Trough triggering the torrential rainstorms during generally drier conditions. Detailed analyses of present-day data from nearby gauging stations confirm that severe rainstorms become more frequent during droughts, and provide more conclusive evidences for late Holocene shifts in synoptic atmospheric circulation patterns. Our late Holocene sediment record from the Dead Sea provides a valuable record of torrential rainstorms, their causative synoptic conditions, and their linkage to the underlying long-term climate trend in the eastern Mediterranean.
ID: 01973, 32.- Large-scale hydroclimate variability and change of the Common Era: Patterns, Impacts, and Processes, (Oral)
Reconstructions of winter and summer hydroclimate in western Tasmania
Kathryn Allen1 , Robert Evans1 , Edward Cook1 , Stuart Allie1 , Fiona Ling1 , Greg Carson1 , Patrick Baker1 1) University of Melbourne, Silviscan Pty Ltd, Lamont Doherty Earcth Obervatory, HydroTasmania, Entura * Kathryn Allen, Kathryn.Allen@unimelb.edu.au
Water resource availability is critical for agriculture, environmental flows, hydroelctric energy production and supply of drinking water. In Australia, short and sparse instrumental records, most of which span < 100 years, limit understanding of hydroclimatic variability. Here we present two seasonal hydroclimatic reconstructions for western Tasmania in southeastern Australia (SEA). In this region water resources are managed on a seasonal basis and there is often little relationship between the hydroclimate of different seasons. Both reconstructions are based on a mixture of ring width and wood properties chronologies (e.g. tracheid radial diameter, cell wall thickness, density, microfibil angle). The first and longest, is a 960-year December - February dam inflow reconstruction. The model explains ~37% of the variance in the calibration period and ~48.5% in the verification period. The reconstruction suggests that summer inflows since ~1900 have generally been close to or below average over the past millennium. The longest dry period occurred around 1500 CE and was accompanied by mean summer temperatures that were well above average. Greater variability is apparent between about 1550 and 1750 CE. The second reconstruction, for the winter period (July-August), is much shorter and also weaker than the summer reconstruction, but verifies back to 1731. It explains ~23% of the variance in inflows and, somewhat unusually, better captures wet rather than dry periods. According to the reconstruction, winters for the past ~150 years have been drier than for the previous ~150 years. Conditions more extreme than those in the
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20th Century have occurred in the past for both seasons. Differences in the reconstructions demonstrate the relevance of highly resolved seasonal information in regions such as SEA, and temperature reconstructions for the same region and season will facilitate more detailed analyses of long-term hydroclimate than have previously been possible for this region.ID: 02142, 13.- Pliocene climate variability over glacial-interglacial timescales (PlioVAR), (Oral)
Late Pliocene-Early Pleistocene oscillations in Mediterranean Overflow water and climate in the Iberian Margin
Montserrat Alonso-Garcia1 , Emilia Salgueiro1 , Teresa Rodrigues1 , Carlos A. Alvarez-Zarikian2 , Warley Soares1 , Ana I. Lopes1 , Henning Kuhnert3 , Ursula Röhl3 , Antje H.L. Voelker1 , Francisco J. Sierro4 , Jose A. Flores4 , Fátima Abrantes1 1) Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, and Instituto Portugues do Mar e da Atmosfera (IPMA), Avda Alfredo Magalhães Ramalho 6, 1495-006 Lisboa, Portugal 2) International Ocean Discovery Program, Texas A&M University, Discovery Drive, College Station, TX 77845, USA 3) University of Bremen, Leobener Str., Marum, 28359 Bremen, Germany 4) Universidad de Salamanca, Pza de la Merced s/n, 37008, Salamanca, Spain * Montserrat Alonso-
Garcia, montsealonso82@gmail.com
The Late Pliocene-Early Pleistocene transition is characterized by a climatic cooling that boosted the expansion of ice-sheets in the Northern Hemisphere and brought the alternation between glacial and interglacial periods. Several hypotheses have been put forward to explain this climate transition, and recently, changes in the production of Mediterranean deep water have been suggested to be an important factor during this transition since this deep water mass contributes high salinity water to the North Atlantic enhancing the whole Atlantic Meridional overturning circulation.
Here we investigated the oscillations in Mediterranean overflow water (MOW) throughout the Late Pliocene and Early Pleistocene using sedimentological and paleontological data from Site U1391 (37° N; 9° W; 1085 m water depth), recovered on the Southwest Iberian Margin during the Integrated Ocean Drilling Program (IODP) Expedition 339. This site is located in a plastered drift in the path of the MOW and offers high sedimentation rates to perform not only high resolution studies of past oceanographic conditions but also to reconstruct climate variability in the region across this transition. In this study, we provide the chronological framework for the bottom part of Site U1391 and combine records of XRF geochemical data (from X-ray fluorescence core scanning), grain-size analysis, benthic foraminifer δ18O and δ13C, and benthic assemblages
(ostracod and foraminifers) to evaluate changes in deep water circulation. Moreover, we reconstructed sea surface temperature conditions to assess the coherence between the regional climate and MOW. The high-resolution record of the XRF analysis (Zr/Al) indicates short-term MOW oscillations very likely related to a precessional pattern, as previously shown for the Mid-Late Pleistocene. However, the grain-size analysis shows a decreasing trend across the study interval, which indicates long-term changes in MOW. Early Pleistocene glacial-interglacial cycles appear to show a stronger coupling between MOW oscillations and sea surface conditions.
ID: 01605, 33.- Ancient DNA for understanding past biodiversity, human history, and drivers of ecosystem changes: achievements, limits and perspectives, (Invited Oral)
Application of HyRAD-X (a method combining reduced representation of the exome and hybridization capture applied to ancient DNA) to time series of subfossil needles unravels the early Anthropocene history of the silver fir, Abies alba, in a population from the southern Alps
Nadir Alvarez1 , Sarah Schmid1 , Christoph Sperisen2 , Willy Tinner3 1) Department of Ecology and Evolution, Biophore Building, UNIL-Sorge, University of Lausanne, 1015, Lausanne, Switzerland 2) Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland 3) Institute of Plant Sciences and Oeschger Centre for Climate Change Research, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
* Nadir Alvarez, nadir.alvarez@gmail.com
Our understanding of the evolution of several emblematic species across millenia has considerably increased in the last decade, thanks to the application of whole-genome capture, in combination with next-generation sequencing. However, to our knowledge, only anecdotical studies have made use of the application of those methods to the impressive time series of tree subfossils available in lake sendiments, to unravel the late Pleistocene and Holocene evolutionary history of forest species. One of the explanations to this gap is the lack of proper reduced genomic representation technique allowing to analyze a large number of ancient DNA samples without applying costly whole-genome capture methods.Here, we present a major update to those methods, namely Hybridization capture from (messenger) RNA to RNA (probes) using RAD-derived probes (HyRAD-X), a technique applying RAD-sequencing to messenger RNA from one or few fresh specimens to elaborate bench-top produced probes, i.e., a reduced representation of the exome, further used to capture homologous DNA from a samples set. As a proof of
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concept, we applied HyRAD-X to subfossil needles from the tree Abies alba, collected in lake sediments at Origlio (Switzerland) and dating back from 7200-5800 years before present (BP). More specifically we investigated genetic variation before, during, and after an anthropogenic perturbation that caused an abrupt decrease in Abies alba population size, 6500-6200 years BP. HyRAD-X produced a matrix encompassing 524 exome-derived SNPs. Despite a lower observed heterozygosity was found during the 6.500-6.200 years BP time slice, genetic composition was nearly identical before and after the perturbation, indicating that re-expansion of the population after the decline was driven by autochthonous specimens. This study outperforms by orders of magnitude previous studies exploring the potential of tree subfossil samples in population genomic studies.ID: 01940, 03.- Regional and transregional climate variability over the last 2000 years, (Oral)
Common Era temperature reconstructions and the response of the climate system to explosive volcanic eruptions
Kevin Anchukaitis1 , Rob Wilson2 , Jessica Tierney3 , Allegra LeGrande4 , NTREND Consortium5 , PAGES2k Oceans2k HR6 1) School of Geography and Development and Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, USA 2) School of Geography and Geosciences, University of St Andrews, UK 3) Department of Geosciences, University of Arizona, Tucson, AZ, USA 4) National Aeronautics and Space Administration Goddard Institute for Space Studies, New York, NY, USA 5) Northern Hemisphere Tree-Ring Network Development (NTREND) Consortium 6) Past Global Changes (PAGES) 2k
Consortium (Oceans2k)
* Kevin Anchukaitis, kanchukaitis@email.arizona.edu Volcanic eruptions cause global-scale changes to the climate system via the direct effect of radiative forcing anomalies and the ensuing influences on and feedback to major modes of ocean-atmosphere variability. Climate model simulations suggest a larger degree of cooling following eruptions than proxy temperature reconstructions, and disagreement persists about the subsequent state of the El Nino Southern Oscillation system. Here, we use two recent temperature reconstructions to investigate the response of the climate systems to volcanic eruptions. Our new NTREND field reconstruction of Northern Hemisphere summer temperatures shows coherent, broad-scale cooling associated with large tropical eruptions: 96% of reconstructed grid points show composite mean colder temperatures and an average response across all grid points and all eruptions of -0.44C. Cooling persists in some cases for 2 or more years following eruptions and different eruptions reveal different magnitudes and
spatial patterns that are not clearly associated with estimated radiative forcing. The PAGES2k Oceans2k High Resolution (HR) reconstruction of tropical sea surface temperatures shows cooling of the western Pacific and Indian Ocean in response to well-dated tropical eruptions since 1600 CE but no statistically significant response in the eastern tropical Pacific, suggesting a reduction in the tropical Pacific temperature gradient but not a canonical El Nino pattern. Climate models simulate an overall larger cooling in the western Pacific and Indian Ocean than the reconstructions and produce a variety of anomalies in the eastern Pacific. Our results here provide a new benchmark comparing proxy reconstructions and model simulations and may help identify possible sources of disagreement.
ID: 01779, 04.- From the Mediterranean to the Caspian: palaeoclimate variability, environmental responses and human adaptive strategies, (Oral)
Holocene Paleoenvironmental Change in the Sierra Nevada, Southern Spain
R. Scott Anderson1 , Gonzalo Jiménez-Moreno2 , Antonio García-Alix2 , Francisco Jiménez Espejo3 , Jaime Toney4 , María Ramos-Román2 , Jose Carrión5 , Carmen Pérez-Martínez6 , María Hernández-Corbalán2 1) School of Earth Sciences & Environmental Sustainability, Northern Arizona University, USA 2) Departamento de Estratigrafía y Paleontología, Universidad de Granada, España 3) Department of Earth and Planetary Sciences, Nagoya University, Japan 4) Geographical & Earth Sciences, University of Glasgow, UK 5) Departamento de Biología Vegetal, Universidad de Murcia, España 6) Departamento de Ecología, Universidad de Granada, España * R. Scott Anderson, Scott.Anderson@nau.edu
The Sierra Nevada region of southern Spain has a rich biological and cultural heritage. Recent paleoenvironmental research in the range includes sedimentary records from several high elevation lakes and bogs, spanning an elevational range of ca. 2500 m to over 3000 m elevation. Common research themes have centered around (1) the impact of climate change and human land use on the fragile alpine ecosystems, as well as (2) the record of more regional human impact on lower elevation landscapes surrounding the mountain range.
The longest (~ 11,500-yr) record comes from the 3020 m asl Laguna de Río Seco (LdRS), where paleobotanical, isotope geochemical and organic biomarker data suggest wet conditions prior to ~ 7.8 ka, and much drier climates after ~ 5.7 ka. These changes are confirmed from additional sites in the range. Progressive aridification of the mid- through late Holocene was periodically interrupted by wetter conditions, such as the widespread Roman Humid Period.
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Signals of human activity within the region and locally within the range are evident in the cores. For example, increases in Pb in sediment occurs during the Early Bronze Age, ~ 3.9 ka. Regionally, increases in charcoal deposition ~ 4.0 ka may result from these activities, rising population levels with changing land-use, or climatic factors. Increasing Olea pollen after ~ 3.0 ka may signify the beginnings of olive cultivation at lowland sites, with major expansion of olive orchards during the 20th century. The periodic Holocene occurrence of the dung fungus, Sporormiella becomes more consistent after ~ 3.0 ka suggest more intensive pasturing. Though Pinus dominated during the early Holocene, it largely disappeared in the pollen record at about this time, suggesting widespread tree-cutting. Only with the establishment of Pinus plantations during 20th century does pine return to importance there.
ID: 01608, 04.- From the Mediterranean to the Caspian: palaeoclimate variability, environmental responses and human adaptive strategies, (Oral)
400 years of summer hydroclimate from stable isotopes in Iberian trees
Laia Andreu Hayles1 , Caroline C. Ummenhofer2 , Mariano Barriendos3 , Gerhard H. Schleser4 , Gerhard Helle5 , Markus Leuenberger6 , Emilia Gutiérrez7 , Edward R. Cook1 1) Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, USA. 2) Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, USA. 3) Department of History and Archaeology, University of Barcelona, Barcelona, Spain 4) Climate Dynamics and Landscape Evolution, German Centre for Geosciences, Potsdam, Germany. 5) Research Center Juelich, Institute of Bio-and Geosciences, Agrosphere (IBG-3); Juelich, Germany. 6) Climate and Environmental Physics, University of Bern, Switzerland. 7) Department of Ecology, University of Barcelona, Spain. * Laia Andreu Hayles, lah@ldeo.columbia.edu
Tree rings are natural archives that annually record distinct types of past climate variability depending on the parameters measured. Here, we use ring-width and stable isotopes in cellulose of trees from the northwestern Iberian Peninsula (IP) to understand regional summer hydroclimate over the last 400 years and the associated atmospheric patterns. Correlations between tree rings and climate data demonstrate that isotope signatures in the targeted Iberian pine forests are very sensitive to water availability during the summer period, and are mainly controlled by stomatal conductance. Non-linear methods based on extreme events analysis allow for capturing distinct seasonal climatic variability recorded by tree-ring parameters and asymmetric signals of the associated atmospheric
features. Moreover, years with extreme high (low) values in the tree-ring records were characterised by coherent large-scale atmospheric circulation patterns with reduced (enhanced) moisture transport onto the northwestern IP. These analyses of extremes revealed that high/low proxy values do not necessarily correspond to mirror images in the atmospheric anomaly patterns, suggesting different drivers of these patterns and the corresponding signature recorded in the proxies. Regional hydroclimate features across the broader IP and western Europe during extreme wet/dry summers detected by the northwestern IP trees compare favourably to an independent multicentury sea level pressure and drought reconstruction for Europe. Historical records also validate our findings that attribute non-linear moisture signals recorded by extreme tree-ring values to distinct large-scale atmospheric patterns and allow for 400-yr reconstructions of the frequency of occurrence of extreme conditions in summer hydroclimate. We will discuss how the results for Lillo compare with other records.
ID: 01607, 04.- From the Mediterranean to the Caspian: palaeoclimate variability, environmental responses and human adaptive strategies, (Oral)
Vegetation dynamics and hydrological response to Holocene climate variability in the Iberian Range: a synthesis from lacustrine and tufa records
Josu Aranbarri1 , Penélope González-Sampériz 2 , Blas Valero-Garcés2 , Ana Moreno2 , Carlos Sancho3 , Graciela Gil-Romera2 , Miguel Bartolomé2 , Marta Alcolea4 , Mª José González-Amuchastegui 1 , Concha Arenas3 , Maria Leunda2 , Donatella Magri5 1) Department of Geography, Prehistory and Archaeology, University of Basque Country 2) Department of Geoenvironmental Processes and Global Change, Pyrenean Institute of Ecology-CSIC 3) Department of Earth Sciences, University of Zaragoza 4) Department of Antiquity Sciences, University of Zaragoza 5) Department of Environmental Biology, Sapienza University of Rome
* Josu Aranbarri, aranbarri.josu@gmail.com
The increase in chronologically well-constrained, palynological, sedimentological and geomorphological sequences obtained from lacustrine and fluvial tufa records along the Iberian Range (NE Spain) has allowed to drawn the vegetation dynamics and the hydrological variability during the Holocene. Overall, three main phases of environmental change can be established. 1) The early Holocene, chronologically comprising 11.700-8200 cal yr BP, is defined as a landscape dominated by montane pinewoods (e.g., Pinus sylvestris/nigra type) and steppe communities (e.g., Artemisia, Compositae, Chenopodiaceae), suggesting a harsh continental climate background. Palaeohydrological proxies reveal low water-stands till 9500 cal yr BP. 2) The most humid phase during
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the Holocene occurred between ca. 8200-5000 cal yr BP and was characterized by the maximum spread of broadleaved elements (e.g., Betula, Corylus, Quercus faginea type), the expansion of a Mediterranean woodland with evergreen Quercus as dominant forest communities and more frequent periods of higher lake levels, resulting in the maximum frequency of tufa deposition at regional-scale. 3) The return of montane pinewoods synchronous to the depletion of broadleaved trees and the decline of tufa growing characterize the mid-late Holocene transition (ca. 5000 cal yr BP). This transition was most likely a consequence of increasing aridity that continued during the late Holocene. Human-pressure is practicably negligible until Roman-times when a rapid region-wide deforestation and the spread of agriculture occurred.ID: 01363, 01.- Open Session on past global changes, (Oral)
Mean ocean temperature evolution in the past 40,000 years from ice core noble gas thermometry
Daniel Baggenstos1 , Marcel Haeberli1 , Thomas Kellerhals1 , Jochen Schmitt1 , Hubertus Fischer1 1) Climate and Environmental Physics & Oeschger Center for Climate Research, University of Bern * Daniel Baggenstos, baggenstos@climate.unibe.chThe amount of heat stored in the ocean is the most robust measure of the integrated energy imbalance of the Earth that accompanies glacial-interglacial climate swings. For the current anthropogenic warming, more than 90% of the excess heat stored by the Earth over the last 50 years is found in the ocean.The history of ocean heat content is thus a central parameter in the reconstruction of global climate forcing and response. Local deep water temperature has been reconstructed using sediment cores, but a truly global signal is difficult to synthesize. The novel method of ice core noble gas thermometry allows us to reconstruct global mean ocean temperature (GMOT) based on simple physics. Because noble gases are passively cycled through the atmosphere/ocean system, and because each gas species has a specific temperature dependent solubility, noble gas ratios in the atmosphere represent a direct, physical proxy for GMOT. After correcting for fractionation effects that happened in the firn column prior to the air getting trapped in the ice matrix, measurements of noble gas elemental ratios in ice cores can thus be used to estimate past GMOT.We present a record of GMOT obtained from EDC ice core samples spanning the last 40,000 years in roughly 1,000 year resolution, highlighting the warming during the deglacial transition. The Last Glacial Maximum GMOT is estimated to 2.6°C colder than present, in good agreement with sediment core oxygen isotope and pore water fluid reconstructions. The early Holocene was slightly warmer than present by approximately 0.5°C. The
GMOT record shows a remarkable correlation with Antarctic temperature, suggesting that the Southern Ocean is an important driver of temperature change in the deep ocean.
ID: 02235, 16.- Multidisciplinary reconstruction of paleofloods, (Oral)
Paleoflood Data and Increasing Flood Extremes
Victor Baker1 1) Dept. of Hydrology and Atmospheric Sciences, The University of Arizona * Victor Baker, baker@email.arizona.edu
The recent, large number of extreme flooding disasters raises questions about the possible role of climatic change. In many cases recent flood extreme magnitudes exceed decadal-scale stream gaging and century-scale historical records. Scientific understanding of extreme flooding absolutely demands real-world data on actual extreme flood events, but this type of data is not provided by either the flood-frequency analysis (FFA) or the mathematical modeling methods (MMM) that totally dominate conventional hydrological science/engineering practice. FFA methods unrealistically extrapolate from small, common floods to provide estimates for unknown, causally unrelated extremes; and MMM cannot create real-world data on the most extreme flooding. It thus follows that truly scientific flood hydrology must pay close attention both to those very rare cases when flood extremes happen and to the existing, very extensive wealth of natural evidence of flood extremes that actually have happened. Paleoflood hydrology provides real-world data on past flood extremes on the millennial time scales that insure representation of the most extreme flooding phenomena. Though miniscule resources have been devoted to this type of flood hydrological science (in comparison what is devoted to conventional FFA and MMM), a survey of existing global paleoflood data, collected by the world’s relatively small cadre of dedicated paleoflood hydrologists, suggests the following preliminary conclusions: (1) recent extreme flood magnitudes are NOT “unprecedented” -- similar extreme flood magnitudes appear in sufficiently long paleoflood records; (2) flood information from the deep past is NOT made irrelevant because of “nonstionarity” in regard to future changes (it is FFA that needs to change, NOT nature); and (3) while future climate change may result in different levels of flood intensity and frequency in particular catchments, these will most probably result from shifts in storm tracks or patterns, evidence for which can only be found in the long-term records of the past.
ID: 02167, 02.- Quaternary climate and environmental change in the Southern Hemisphere, (Oral)
